clean up sphinx warnings

- fixed missing blank line in ref docs code block
- updated references to sphinx docs
- included documentation notes into the docs index

Signed-off-by: Joe Heck <heckj@mac.com>

docs/devel/generate-docs.rst

@@ -2,8 +2,10 @@
 Generating Documentation
 =====================
 
-The documentation uses `Sphinx`_ (via `Read The Docs`_) to generate markdown
-from `reStructured Text`_.
+The documentation is generated from `reStructured Text`_ by `Sphinx`_
+(via `Read The Docs`_). If you're unfamiliar with `reStructured Text`_,
+the files typically have the extension `.rst`. You can find more details
+in the `reStructured Text Basics`_.
 
 Installation instructions
 =========================
@@ -29,6 +31,7 @@ open with your browser.
 Note that you do not need to add these files to your git client, as
 *Read The Docs* will generate the HTML on the fly.
 
-.. _`Sphinx`: http://www.sphinx-doc.org/
+.. _`Sphinx`: https://www.sphinx-doc.org/
 .. _`Read The Docs`: https://readthedocs.org/
-.. _`reStructured Text`: http://www.sphinx-doc.org/en/master/usage/restructuredtext/index.html
+.. _`reStructured Text`: https://www.sphinx-doc.org/en/master/usage/restructuredtext/index.html
+.. _`reStructured Text Basics`: https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html

docs/reference/issuers/acme/http01.rst

@@ -29,6 +29,7 @@ using Ingress resources
 In rare cases it might be not possible/desired to use NodePort as type for the http01 challenge response service, e.g. because of Kubernetes limit restrictions. To define which Kubernetes service type to use during challenge response specify the following http01 config
 
 .. code-block:: yaml
+
        http01:
          # Valid values are ClusterIP and NodePort
          serviceType: ClusterIP